From: Matthew Wilcox (Oracle) <willy@infradead.org>
Date: Thu, 14 Apr 2022 06:07:21 +0000 (-0700)
Subject: fork: use VMA iterator
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=000b68a9ae5fa170bb6cb68ca6080ba67a24ea3b;p=users%2Fjedix%2Flinux-maple.git

fork: use VMA iterator

The VMA iterator is faster than the linked list and removing the linked
list will shrink the vm_area_struct.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---

diff --git a/kernel/fork.c b/kernel/fork.c
index 20890be1371b..fa0ec0783784 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1288,13 +1288,16 @@ int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
 	/* Forbid mm->exe_file change if old file still mapped. */
 	old_exe_file = get_mm_exe_file(mm);
 	if (old_exe_file) {
+		VMA_ITERATOR(vmi, mm, 0);
 		mmap_read_lock(mm);
-		for (vma = mm->mmap; vma && !ret; vma = vma->vm_next) {
+		for_each_vma(vmi, vma) {
 			if (!vma->vm_file)
 				continue;
 			if (path_equal(&vma->vm_file->f_path,
-				       &old_exe_file->f_path))
+				       &old_exe_file->f_path)) {
 				ret = -EBUSY;
+				break;
+			}
 		}
 		mmap_read_unlock(mm);
 		fput(old_exe_file);